Liquid fuel burning heater and operating system therefor



June 23, 1953 5. J. BUDLANE 2,642,933

LIQUID FUEL BURNING HEATER AND OPERATING SYSTEM THEREFOR Original Filed Sept. 7, 1946 5 Sheets-Sheet l I WW Wm SELECTOR HEATER MOTOR 5 ozmosr:

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LIQUID FUEL BURNING HEATER AND OPERATING SYSTEM THEREFOR Original Filed Sept. 7, 1946 5 Sheets-Sheet 2 rung -15mm;

June 23, 1953 5. J. BUDLANE ,6

LIQUID FUEL BURNING HEATER AND OPERATING-SYSTEM THEREFOR Original Filed Sept. 7, 1946 5 Sheets-Sheet s wxw June 23, 1953 S. J. BUDLANE LIQUID FUEL BURNING HEATER AND OPERATING SYSTEM THEREFOR Original Filed Sept. 7, 1946 5 Sheets-Sheet 4 June 23, 1953 5. J. 'BUDLANE 2,642,933

LIQUID FUEL BURNING HEATER AND OPERATING SYSTEM THEREFOR Original Filed Sept. 7, 1946 5 Sheets-Sheet 5 I fizz/6222 07 I Sfan/ay J Bud/ans .I

Patented June 23, 1953 LIQUID FUEL BURNING HEATER AND OPERATING SYSTEM THEREFOR Stanley J. Budlane, Chicago,- Ill., assignor to Motorola, Inc., Chicago, Ill., a corporation of Illinois Original application September 7,1946, Serial No. 695,478, now Patent No. 2,588,349, dated March 11, 1952. Divided and this application February 26, 1949, Serial No. 78,609

4Claims. (01.158-28) This invention relates to liquid fuel-consuming heaters, and particularly to means for automatically controlling the operation of such heaters.

The present application is a division of the co-pending application of Robert Dusek and Stanley J. Budlane, Serial No. 695,478, filed September '7, 1946, which has now issued as Patent No. 2,588,349.

In the operation of a combustion heater which utilizes a liquid fuel, one encounters several problems which are not present in the operation of a heater utilizing a combustible gas supplied by an outside source. To obtain an efficient, high-capacity heater, provisions must be made therein to condition the liquid fuel for combustion. One way of doing this is to break up or atomize the liquid fuel particles by mechanical action. Heaters of this type are relatively bulky and require a large amount of power for their operation; consequently they are generally not considered satisfactory for use in comparatively smallinstallations. On the other hand, a heater which conditions the fuel by the application of heat thereto has been found to be Well adapted for use in comparatively small installations. A heater of this type produces a large heat output without requiring a large amount of power for its operation, and it can be used to good advantagefor heating vehicles or other enclosed spaces such as rooms.

I have found that a heater which operates on the heat-conditioning principle gives very excellent results when the conditioning of the fuel is performed in at least two stages. First, a small quantity of liquid fuel is supplied to a pilot burner and is heated to the vaporization point. Air is mixed with the fuel vapor in the correct proportions to produce a combustible mixture which then is ignited at the pilot burner to produce a pilot flame which burns continuously while the heater is in use. Only a very small amount of power is needed to condition and ignite the pilot fuel.. Hence, electrical devices which do not consume much power may be employed for this purpose. Once a pilot flame is established, the heat from this flame may be used to condition fuel in relatively large quantities for supplying a combustible mixture to a main burner or main burners and also to the pilot burner itself. The main burner or burners (which may operate intermittently while the heater is in use) then will supply the necessary heat required to fulfill the demand made upon the heater. A heater of this character is disclosed in the aforesaid copending application of Robert Dusek and Stanley J; Budlane.

An object of the present invention is to provide a novel automatic operating system for a heater which performs the functions described above.

A further object is to provide an improved heater operating system which automatically governs the fuelconditioning, fuel ignition and fuel feeding operations in a liquid fuel-consuming heater having pilot and main burners as described above.

A still further object is to provide a practical and inexpensive heater operating system whereby the use'of liquid fuel-consuming heaters in vehicles and in other small or medium-sized installations will become more popular than has been the case heretofore. More specifically, it is an object to provide a system which will more effectively demonstrate the merits of the heatconditioning-principle from a practical standpoint.

Another object is to provide a heater having an automatic operating system whereby liquid fuel is heated, vaporized and ignited in a plurality of stages and in which the fuel supply is regulated in accordance with heat requirements, all; of these functions being performed without manual intervention.

Yet another object is to provide a simple and economical operating system which, in response to the mere closing of a switch, starts a liquid fuel-consuming heater in operation and thereafter maintains such heater in operation, such system automatically causing the liquid fuel to be vaporized, mixed with air, supplied to a pilot burner and ignited to produce a pilot flame, also causing other liquid fuel from the same source to be heated, vaporized and supplied to a main burner'or burners to be ignited by the pilot flame, utilizing the heat. from the pilot flame to maintainzthe. fuel conditioning process so that the initial fuel. conditioning and igniting means may be removed from operation, and selectively regulating the feeding of liquid fuel to at least the main burner structure so as to maintain a predetermined temperature in the space that is being heated.

V The terms pilot burner and main burner are used herein for the purpose of convenience and are notintended to limit the scope of the invention in any way. The pilot burner is any burner which maintains a relatively small flame for fuel conditioning or fuel ignition purposes, or both, and its fuel consumption is large by comparison with that of the pilot burner. Usually, the main burner structure supplies substantially all of the useful heat output of the heater, at least under normal conditions of operation, and its fuel consumption rate is variable in accordance with heat requirements.

The term fuel conditioning as used herein denotes the process by which the fuel is prepared for combustion. In the present instance this comprises heating the fuel to an effective vaporization temperature in the presence of an air stream, whereby the fuel vapor mixes with the air to form a combustible fuel and air mixture.

A feature of the invention resides in the combination of 1) electrically operated means for starting the pilot burner, and (2) mechanical heat-transfer means responsive to the pilot flame for maintaining the pilot burner in operation, once it is started, and for enabling the main burner or burners to operate in response to the operation of the pilot burner. As stated above, the operation of the main burner or burners may be intermittent, depending upon the demand for heat, while the pilot burner operates continuously during the time that the heater is in use.

Another feature is the provision of means for effecting an automatic, multi-stage fuel condi tioning operation. Conditioning of the pilot burner fuel is initiated in response to the operation of the electrical starting means just mentioned. Conditioning of the main burner fuel (as well as the conditioning of the pilot burner fuel after the initial step) is effected by transferring heat from the pilot flame to the liquid fuel 30 as to vaporize the same rapidly. The supply of liquid fuel to the main burner fuel conditioning means is regulated automatically in ac cordance with heat requirements.

As another feature, the electrical starting means is automatically removed from operation when a pilot flame is established, and is automatically restored to operation if the pilot flame should fail. 7

An additional feature is the selective control of air temperature by means of push buttons or other manually settable means. An expansible thermal element responsive to air temperature controls fuel valves to vary the fuel feeding rate in accordance with heat requirements. An electric heating element controlled by the push buttons also affects this thermal element. The fuel feeding rate can be modified by varying the electrical power consumption in the heating element, thereby determining the air temperature which will be maintained by the heater.

The foregoing and other objects, features and advantages of the invention will be apparent from a consideration of the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a perspective view of a heater embodying the invention, as installed in a vehicle;

Fig. 2 is a cross-sectional view of the heater of Fig. 1;

Fig. 3 is a detailed view of the base plate of the heater;

Fig. 4 is a perspective view illustrating the operating components of the heater;

Fig. 5 is an exploded View showing the manner in which the major components of the heater are positioned relative to each other;

Figs. 6 to 9 show details of the burner construction; and

Fig. 10 illustrates schematically the operating system of the heater.

The embodiment of the invention illustrated herein is adapted for use in an automobile to heat the interior thereof. The heater includes a hollow base member, a C-shaped combustion chamber mounted on the base member, and an electric motor which is partially surrounded by the combustion chamber. The motor drives a fan for supplying combustion air to the heater and another fan which circulates the air from the interior of the vehicle into contact with the exterior of the combustion chamber for heating the air. The base member has a chamber in which the combustion air is preheated, and another chamber through which the exhaust gases pass from the combustion chamber. The heater has a housing which serves to guide the circulating air through the heater. At one end of the combustion chamber there is located a burner unit including a pilot burner and a plurality of additional or main burner passages. Fuel feeding means positioned within the housing between the ends of the combustion chamber is arranged to feed fuel selectively to these passagesdepending upon the heat output required.

The operating system for the heater comprises the necessary electrical and mechanical parts for performing the various control functions which have been explained above. There is, for example, a starting circuit for placing the heater in operation from a cold condition. This starting circuit, in response to the closure of a switch (which switch also is effective to start the fuel pump operating), electrically heats the fuel supplied to the pilot burner for conditioning the same, and causes the conditioned fuel to be ignoted. The burner unit is so arranged that heat from the pilot flame is rapidly conducted to the Walls of the pilot and main burner passages. The heat thus conducted to the burner passages is effective to condition the fuel therein so that eflicient combustion of the fuel takes place in the burners. Thermal means responsive to the temperature of the combustion chamber automatically disconnects the starting circuit when the combustion chamber attains a predetermined temperature. Other thermal means responsive to the temperature of the circulating air regulates the fuel supply to the main burners in accordance with heat requirements. Modification of these heat requirements is effected by a separate control circuit which energizes an electric heating element in the vicinity of the secondmentioned thermal element, the amount of such energization being selected according to the variation of heat output that is desired. Thermal safety means included in the system causes the fuel pump to cease operating if combustion fails or if no ignition of the fuel takes place within a predetermined time.

Referring now to the drawings, in Fig. 1 the heater I0 in accordance with the invention is shown mounted on the cowl l l of an automobile under the dash I2. The heater is mounted by a plurality of bolts l3 and includes conduits l4 extending through the fire wall for providing intake and exhaust of combustion air. The heater includes a grille l5 through which air from the passenger compartment of the automobile enters the heater. An annular opening I6 is provided through which the heated air is forced into the passenger compartment. Con- V garages duits I T are provided for admitting heated air to the defroster slots 18 normally provided in the dash adjacent the windshield. For the purpose of providing fuel for the heater from the vehicle fuel system, a fuel feed line I9 is provided. A cable 2!] makes electrical connections to the heater from the push button control head 2i as will be hereinafter-explained. The fuel feed line and cable enter the housing through suitable connectors in a removable portion 22 of the housing which is provided to furnish access to the operating components of the heater as will be presently explained.

For a description of the detailed structure of the heater, reference is made to the Figs. 2, 3, 4 and 5 in which the heater is shown having a base member 23 on which a motor 24 is mounted as by brackets 25. A c-shaped combustion chamber 26 is positioned about the motor as is clearly shown in Figs. 2 and 5. The base member 23 together with the bottom plate 21 secured thereto define a plurality of chambers. An intake air chamber 28 is provided therein into which air enters through opening 29 in the base plate 21. After the air is preheated in the chamber 28 in the base member, it passes through opening 30 therein to the burner housing 31 which is secured to the combustion chamber 26. The base member also has an exhaust chamber 32 therein connected through opening 33 to the exhaust end 3 5 of the combustion chamber. A fan 35 driven by motor 24 is positioned in'the chamber 32 to cause a suction therein for exhausting the combustion air through opening 38 in the base plate. It is, therefore, seen that a complete passage for combustion air or gases I is provided through the intake chamber in the base plate into the burner housing then through the combustion chamber to: the exhaust end thereof and into the exhaust chamber in the base plate where the suction fan causes the air or gases to be exhausted from the heater. This passage is shown by the arrows in Fig. 5.

The housing as inclosing the heater structure is also secured to the base member 23 and cooperates with the motor 24 and combustion chamber 26 to form a passage for air to be heated between the motor and combustion chamber to the base member and thence between the combustion chamber and the housing to the open end of the housing. Secured to thetop of the combustion chamber is a plate 4| on which is supported a cylindrical member 42 and a stationary air guide 43, best seen in Fig. 5, for directing the air entering the heater. Above the stationary guide 43 is an axial fan 44, also driven by motor 24, for the purpose of drawing air into the heater. The air guide 43 functions to straighten the flow of air entering the heater and reduces the turbulence thereof. A cover member 45 is provided across the open end of the housing having an opening 46 therein over which grille I5 is placed. The plate 4|, cylindrical member 42 and air guide 43 form an assembly which is supported on casting 26. Openings 4'! are provided in plate! which register with projections-4B on casting 26 to secure the assembly to the casting (Fig, 2); The cover member may be secured to the platev 41 by' any suitable means such as by clips 49 secured to the plate'4i. The air, after passing about the combustion chamber and being heated, leaves the housing through annular opening 16 between the plate 4! and the housing 49. V As is apparent from Figs. 4' and 5,]the" burner and fuel feeding means. are positioned in an arcuate portion between the ends of the combustion .chamber 26. Fuel isdrawn into the heater by the fuel pump 50 through fuel line 5| and is then supplied through fuel line 52 to pressure regulator 53 and through fuel line 54 to selector 55. The fuel pump and pressure regulator may be of any standard construction, the selector preferably being ofthe construction disclosed in the co-pending application of Stanley J. Budlane, Serial No. 644,693 filed February 1, 1946 which has now issued as Patent No. 2,588,348. The selector provides fuel through fuel lines 56 to a pilot burner and a plurality of additional burning passages as will be later described. The arcuate portion is divided off by the burner housing 31 and by insulating members 51 and'58 as shown in Fig. 5. The insulating member 51 has an opening 59 therein permitting a limitedamount of air drawn in by the fan 44 to. enter the arcuate portion. The fuel pump, pressure regulator and selector are supported on a bracket 6!] which is mounted on the insulating member 58. As described in the above mentioned application, the selector includes a temperature responsive element 6i which controls the supply of fuel to the fuel lines 56. This element iii, in. the present instance, is. a thermally expansible bellows which actuates a plurality of needle valves (not shown) in the selector 55 for closing and opening the fuel lines 56 in selected numbers. A housing 62 is provided for the temperature responsive element having a neck portion 63 which forms a conduit for directing a portion of the air entering the arcuate portion through opening 59 int-o the housing so that it comes in contact with the temperature responsive element. A heating coil 64 is provided in the neck portion 63 to selectively heat the air before contacting the temperature responsive element in a manner to be described. As is apparent from Figs. 1, 2, 4 and 5, the grille [5 extends back to a defroster housing 65 to which heated air is admitted through the opening [6 at the top of the housing. The housing 65 has opening 66, best seen in Fig. 1, therein to which the defroster conduits I! are attached. A slide 61 having an actuating lip 68 is provided for selectively furnishing heated air to the conduits.

Reference is now made to Figs. 6, 7,- 8 and 9 in which the details of the burner structure are shown. The burner is provided with a housing 3| having a plurality of openings therein utilized as burning passages, with a cover plate l0 secured thereto to provide a passage H which is adapted to receive combustion air from the base member 23 through the opening as therein. The cover plate 10 has an opening therein in which a pilot burner #2 including an igniter is mounted and a plurality of additional openings to receive the fuel feeding lines 56. The igniter includes an electrical heating coil'l3 having a portion supported by a ceramic cylindrical member 14 and an exposed portion 15. The igniter is arranged to be connected to a source of electrical power through terminal 76; the other end being grounded through the heater housing. The ceramic member 14 of the igniter is surrounded by a pair of spaced cylindrical members i! and 18, the member 18 having an opening l9 therein through which air and fuel are admitted to the annular passage between the members. A cupshapedportion Si] is provided on the cover plate 'lflinto which fuel is admitted through one of the fuel lines 56 and through which air is admitted from passage II. Fuel and air are mixed in the portion 80 and fed to the annular passage in the pilot burner. This mixture is heated as it traverses the passage causing the fuel to be vaporized and when the mixture reaches the end of the cylindrical member 11 it is ignited by the exposed portion I of heatin coil I3. Due to the current of air through the burner, caused by the suction of fan 35, the flame will move to the ports 8| in the front plate 82 of the burner after combustion has started. The igniter will be de-energized when combustion is started but combustion will continue and a continuous pilot flame will be developed through ports 8 I. Since the burning does not take place directly at the coil, the coil will not be in danger of becoming burned out because of the high temperatures.

As shown by the dotted lines in Figs. '7 and 9, additional burners 85 (referred to as main burners elsewhere herein) are provided about the pilot burner I2. These additional burners are shown in detail in Fig. 8. The burners 85 include cylindrical ceramic liners 86 positioned in openings 81 in the housing 3| and small tubular members 88 secured to the housing and extending within the ceramic liners. Conduit members 89 connected to the fuel feeding lines 56 provide for the entry of fuel between the tubular members 86 and 88 and air entering through passage II enters through tubular member 88 and also through the opening 90 about conduit 89 into the passage between the tubular members 86 and 88. The heat from the pilot burner heats the entire burner housing 3I and, therefore, the air and fuel mixture traversing the burner passages becomes heated. Contact of the fuel with the hot ceramic liners causes vaporization thereof so that a combustible mixture is provided which passes through the ports 9! in the front plate 82. As clearly shown in Figs. '7 and 9, a deflector 92 is provided over the ports 8| of the pilot burner. This deflector causes the flame from the pilot burner to circulate to provide efficient burning and has openings 93 therein through which a portion of the flamerfrom the pilot burner may escape. The openings 93 are directed toward the ports SI for the additional burners so that the flame from the pilot burner ignites the mixture from these burners. Deflector members 94 are provided over the ports 9| so that the flame from the burnin passages tends to circulate causing all the mixture to become ignited to thereby provide efficient combustion.

The control circuits involved in the operating system of the heater are illustrated schematically in Fig. 10. The push button control head 2| is connected to a source of potential IOI such as the storage battery of an automobile and is connected to the operating components of the heater through plug I02 and receptacle I03. The control head 2| includes five push buttons I04, I05, I06, I01 and I08 which are mechanically interlocked so that when any button is depressed the other push buttons are automatically released. It is noted that the two sets of contacts I00 and I09 associated with push button I04 are adapted to be opened when the push button is depressed and the contacts II 0, III and II 2 associated with push buttons I05, I06 and I01, respectively, are arranged to be closed when the push buttons are depressed. Although contacts are shown associated with push button I08, these contacts are not used, the only function of push button I08 being to release each of the other push buttons.

It is apparent that any standard push button switch assembly may be used in the control panel, the only requirements being that the contacts are sufliciently heavy to carry the currents involved and that one push button opens two sets of contacts and the other push buttons each close the associated contacts. For this reason the mechanical details of the push button switch will not be described.

When operation of the heater is not desired, the push button I04 indicated on the drawing as Off will be depressed and contacts I00 and I09 will be opened. When operation of the heater is desired, any one of the push buttons I05, I06, I01 or I08 will be depressed and the switch contacts associated therewith will be closed as well as the switch contacts I00 and I09 as the switch button I04 will return to its normal position because of the mechanical interlock. This will apply the potential from the battery IOI through contacts I09 to the conductor II3 which is connected to the terminal marked a of plug I02. When the plug and receptacle are engaged this will energize terminal a of receptacle I03, and make a connection through conductor II4 to motor 24 and contact I I5 of thermostatic switch H6. The closing of contacts I00 will connect conductor II'I which energizes a pilot light H8 and terminal 0 of plug I02. Connection is made through terminal 0 of receptacle I03 to conductor H9 which energizes contact I20 of thermostatic switch and contact I2I of safety switch I22. Thethermostatic switch II6 may be of any standard construction and in addition to the movable contacts H5 and I20 includes stationary contacts I23 and I24. The movable contacts are moved by a suitable temperature responsive element from the position shown, when the element is cold to a position in which the contacts I20 and I23 are broken and the contacts H5 and I24 are engaged when the element is hot. The movable contacts H5 and I20 are insulated from each other. The thermostatic switch is mounted on the combustion chamber as shown in Fig. 2

adjacent to the burner to be controlled by the temperature thereof.

When the combustion chamber is cold the contacts I20 and I23 will be closed to thereby apply potential to the conductor I25 which energizes igniter I3 and to the conductor I26 which energizes the heating coil I21 of the safety switch I22. The safety switch I22 is arranged so that the contacts |2I and I28 thereof will normally be closed providing a circuit to the pump 50. Although the pump 50 may be of any standard construction, a solenoid operated pump is illustrated having a coil I29 for driving the same and a pair of contacts I30 for interrupting the circuit through the solenoid in a well known manner. A condenser I3I is bridged across the contacts I30 to eliminate sparking thereof. After the heater has been started and the combustion chamber becomes hot, the thermostatic switch II6 will move to the lower position with the contacts I20 and I23 opening to de-energize the igniter 13 and the heating coil I21 of the safety switch.

The safety switch I22 is a slow acting bi-metal switch which requires that the heating coil I21 be energized for a relatively long time before the switch contacts I2I and I28 will open. The purpose of this switch is to stop the pump and thereby stop the flow of fuel to the combustion chamber in the event that ignition of the fuel 9 does not take place. For this reason, the switch must allow sufficient time for combustion to start before opening the contacts i2] and I23.

The contacts H and I24. of the thermostatic switchare closed when the combustion chamber is hotproviding a parallel circuit for the motor through conductor I32. This conductor is connected through terminal 2) of receptacle [t3 and terminal b of the plug H32 directly to the battery iii! and is always energized. This parallel circuit will remain closed after the main switch contacts we are opened until the combustion chamber cools off and the thermostatic switch moves to the upper position breaking the contacts M5 and H4. This arrangement permits the fan .33 to clean out the combustion chamber after-combustion ceases to condition the heater for the next use.

In addition to the main operating circuit as above described, an auxiliary circuit is provided through the push button switches Hi5, ltd, [ill and Hill for control of the heating coil st associated with selector As previously statedtheselector 55 includes a temperature responsive element 6! over which air entering the heater is passed to control the supply of fuel to the heater in accordance with the temperature of the incoming air. In order to provide a system whereby the air in the space to be heated is heated to any temperature desired, the heating coil 64 is provided when the air in predetermined amounts before it comes in contact with the temperature responsive element to thereby change the temperature range to which the element is responsive. In a specific application the temperature responsive element 51 is arrangedto control the how of fuel to the heater so that the temperature of the air in the space to be heated (the temperature of the air entering the heater) is 80 F. If it is desired that the temperature in the space to be heated be only 70 i i, the heating coil 54 can be energized to increase the temperature of the air entering the selector so that the temperature of the air contacting the temperature responsive element is actually 80 F. This operation is described in detail in application Serial No. (M4593 referred to above. To provide selective heating by the heating coil 84, contacts Ht, HI and H2 and resistors 153 and 13s are provided. It is apparent that when push. button M35 is depressed, the coil 64 will be connected through contact HE) directly to the voltage of the battery i6! causing the coil 6 to produce the maximum amount of heat. This will, of course, cause-the air contacting the temperature responsive elements of the selector to be heated a great amount and the selector to therefore feed a small amount of fuel with the result that the space to be heated will be held at relatively low temperature. Operation of push button H38 will cause the heating coil. 54- to be connected to the battery it! throughcontacts l i and resistor [33 causing the current through coil to be less and the heating of the air by the coil to be correspondingly less. This will cause the selector to feed more fuel to provide a higher temperature in the space .to'be heated. Operation of push button l il will cause the heating coil to be connected to the cattery through ;contacts 1 K2 in series with resistors 1-33 and Hi l causing a still smaller current through the coil as and ---a correspondingly higher temperature in the space to be heated. When the push button lull is opera-ted the heating coil lid is completely de-energized and the temperature responsive element 6! is responsive to the temperature for which it is naturally designed. This will provide a higher temperature in the space to be heated than when heating coil 55 is energized. It is apparent that by proper design of a temperature responsive element and by proper selection of the coil G l and resistors i3 3 and E34, the push buttons I05, Hill, It? and I58 can be made to provide any four temperatures desired. These buttons may be marked 50, 60, '70 and 30 indicating that in a particular application the components are designed to provide temperatures of 50, 60, '70 and 80 degrees Fahrenheit. If finer adjustments of temperature are desired, more push buttons and more resistance elements can. of course, be provided.

The operation of the heater as described above will now be set forth. The temperature to which the automobile is to be heated will be chosen in accordance with the desires of the persons in the automobile, the outside temperature generally being an important consideration. Let us assume that a temperature of 70 F. is desired and the pushbutton marked 70 is actuated. This will cause the motor to operate to circulate air through the combustion chamber as well as circulate air from the automobile through the heater. The pump will deliver fuel to the selector through the pressure regulator and the igniter and heating coil of the safety switch will be energized. The selector will deliver fuel to the pilot burners and may also deliver fuel to the additional burners depending on the temperature of the air entering the heater. The fuel entering thepilot burner is heated by the igniter, mixed with air, and then ignited by the exposed end of the iigniter coil. This causes the combustion chamber to become hot and the air being circulated through the heater to be heated. The combustion chamber will soon reach a sufficiently-high temperature to cause the thermostatic switch to operate to cut off the igniter and the heating coil of the safety switch. It is to be noted that if combustion did not take place, the safety switch would, after a predetermined time, out off the fuel pump so that a large amount of fuel would not accumulate in the burner which might create a hazard.

As the air in the automobile is heated, the temperatureof the air. entering the heater from the automobile will be raised so that the selector will deliver less fuel to the burners. Accordingly, if the automobile was very cold when the heater was started, all the burners would be supplied with fuel immediately and a very large amount of heat would be provided. If the outside temperature is very .low, it may be necessary forall the burners to continue operation to heat the automobile to the desired temperature. However, the .heat output of the heater is so -.great that the automobile will. usually heat up so that fuel will be supplied to only a part of the burners and perhaps only to the pilot burner. =It ispointed out here that fuel is fed-.to thepilot burner at a fixed rate all the time that the heater is operating but fuel is fed to the additional burners in accordance with the heat output required and varying amounts maybe fed to each burner. This is fully explained in application Serial No. 644,693, referred to above. Therefore, the pilot burner always operates while the heater is operating and supplies a small amount of heat for heating 1 the automobile as well as serving .to condition andignite .fuel which may be supplied to the 11 other burners. This permits the heat output of the heater to be changed very rapidly and to vary through a wide range.

When the heater is turned off by the push button switch the fuel pump will be de-energized causing combustion to stop but the motor will remain energized through the thermostatic switch as long as the combustion chamber is of such temperature to hold the switch in the hot position. This causes the circulation of air to continue through the combustion chamber to clean out any residue of fuel or exhaust gases therein so that the burner will be in proper condition for a subsequent operation. The heater cannot be started until the combustion chamber is cooled off as the igniter will not be energized until the thermostatic switch is in the cold position. The continued operation of the pump also circulates air through the heater to thereby lower the temperature of the heater very rapidly. When the combustion chamber has cooled down to a predetermined temperature, the thermostatic switch will operate to disconnect the motor and the heater is completely de-energized.

The invention has been described above in connection with a burner unit comprising a pilot burner 12 and additional burners 85, which constitute the main burner structure. The invention would be applicable also to an arrangement having a first pilot or fuel-consuming igniter, a second pilot and a main burner structure. In this instance, the igniter fuel would be conditioned and ignited by electrical means substantially in the same way that the pilot burner fuel is handled in the system disclosed above. The igniter flame could then be used to heat the fuel supplied to the second pilot to condition the same for combustion. The second pilot would be lighted by the igniter flame and in turn establish a pilot flame for conditioning and igniting the fuel utilized by the main burner or burners and by this pilot burner. The second pilot, therefore, would correspond to the pilot burner shown in the present disclosure, and the igniter or first pilot would be the starting means for it.

While the invention is shown as being embodied in an automobile heater, it is of general application to both vehicular and stationary heater installations. It automatically governs the feeding, vaporization and combustion of the fuel in a plurality of stages without any manual intervention other than turning the heater on and setting it for the desired temperature. By arranging the electrical fuel conditioning and igniting means in a small burner such as the pilot burner 12, where it is exposed to only a small flow of fuel and air, I avoid many design problems which would be encountered if these parts were located in a larger burner having a greater flow of fuel and air. Furthermore, the constantly burning pilot flame furnishes suflicient heat for conditioning the fuel supplied to both the pilot and main burners; hence the electrically operated conditioning means is used only to start the heater. Thereafter the pilot flame maintains a heat reservoir to condition the fuel as needed by itself and by the intermittently operating main burner or burners.

The above-mentioned and other advantages of the disclosed system have been fully pointed out in the detailed description. Modifications of this embodiment possessing like advantages may occur to those skilled in the art. It is intended that all modifications which utilize the novel teachings of the present disclosure shall be included within the scope of the appended claims.

I claim:

1. A liquid fuel burning heater system including in combination, a compact heat conducting burner structure having therein a pilot burner and at least one main burner, each of said bumers including a burner port and a passageway communicating with said port, electrically operated means for supplying liquid fuel to said passageways, means for supplying combustion air to said passageways, electrical starting means for said pilot burner positioned in the passageway thereof for heating and vaporizing the liquid fuel supplied thereto and for igniting the conditioned fuel whereby a pilot flame is established at the burner port thereof, said burner structure including deflector means at said pilot burner port for deflecting the flame thereof against said structure for heating said passageways whereby vaporization of the fuel supplied therethrough is effected, and a control circuit connected to said electrically operated fuel supply means and said electrically operable starting means including a main switch for energizing the same, temperature responsive means for selectively controlling the flow of fuel to said passageways, and thermal means responsive to the temperature of said burner structure for disabling said starting means when said burner structure reaches a predetermined temperature.

2. A liquid fuel burning heater system including in combination, a heat conducting burner structure having formed therein a plurality of burner ports and a plurality of passageways communicating with said ports, electrically 0perated fuel handling means for supplying liquid fuel to said passageways, means for supplying combustion air to said passageways, electrically operable starting means positioned in at least one of said passageways for heating and vaporizing liquid fuel supplied thereto for conditioning said fuel for combustion and igniting the conditioned fuel, whereby a pilot flame is established at the burner port associated with said one passageway, said burner structure including deflector means at said last mentioned burner port for deflecting said pilot flame against said structure for heating said passageways whereby vaporization of the fuel supplied therethrough is effected and a control circuit for controlling said fuel handling means and said starting means, including a main switch for energizing the same, temperature responsive control means regulating the rate of fuel delivery from said fuel handling means to said passageways, and thermal means responsive to the temperature of said heat conducting member for disabling said starting means when said heat conducting member reaches a predetermined temperature.

3. A liquid fuel burning heater system including in combination, a heat conducting burner structure having formed therein a plurality of burner ports and a plurality of passageways communicating with said ports, electrically operated fuel handling means for supplying liquid fuel to said passageways, a combustion air manifold communicating with said passageways, electrically operable starting means positioned in at least one of said passageways for heating and vaporizing liquid fuel supplied thereto for conditioning said fuel for combustion and igniting the conditioned fuel, whereby a pilot flame is established at the burner port associated with said one passageway, said burner structure inregulating the rate of fuel delivery to said passageways, and thermal means responsive to the temperature of said heat conducting member for disabling said starting means when said heat conducting member reaches a predetermined temperature.

4. A liquid-fuel consuming internal combustion heater including in combination: a heatconducting burner structure having a pilot burner passage extending therethrough terminating in a pilot burner port at the front of said structure, and further having at least one main burner passage extending therethrough in heatconducting relationship with said pilot burner passage and terminating in a main burner port at the front of said structure in igniting relationship with said pilot burner port; an electrical heating element disposed in said pilot burner passage; means for supplying liquid fuel to said passages; means for supplying air under pressure to said passages; switching means for initially closing an energizing circuit to said electrical heating element causing said element to heat said pilot burner passage to vaporize the liquid fuel supplied thereto so that a combustible air-and-fuel mixture is supplied to said pilot burner port, and further causing said element to ignite said combustible mixture so that a pilot flame is developed at said pilot burner port; defleeting means for directing said pilot flame to heat said burner structure and vaporize the liquid fuel supplied to said main burner passage so that a combustible air-and-fuel mixture is supplied to said main burner port and ignited by said pilot flame; a thermal-responsive element for actuating said switching means to'open said energizing circuit to said electrical heating element when said burner structure reaches a selected temperature; and a thermal-responsive element coupled to said fuel-supply means for interrupting the fuel to said main burner passage when said burner structure reaches a selected temperature higher than said first-mentioned selected temperature.

STANLEY J. BUDLANE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,394,807 Blanchard Dec. 4, 1920 1,529,906 Morris Mar. 17, 1925 1,832,220 Kerrihard et al. Nov. 17, 1931 1,841,463 Barber et al. Jan. 19, 1932 2,007,714 Gauger July 9, 1935 2,074,168 Danuser et al. Mar. 16, 1937 2,115,988 Furlong May 3, 1938 2,192,632 Beam Mar. 5, 1940 2,286,853 Holthouse June 16, 1942 2,286,854 Holthouse June 16, 1942 2,489,716 McCollum Nov. 29, 1949 

